**Given : **A rhombus ABCD whose diagonals intersect each other at O.

**To prove : **A circle with AB as diameter passes through O.

**Proof : **∠AOB = 90°

[Diagonals of a rhombus bisect each other at 90°]

⇒ ∆AOB is a right triangle right angled at O.

⇒ AB is the hypotenuse of A B right ∆AOB.

⇒ If we draw a circle with AB as diameter, then it

will pass through O. because angle is a semicircle is 90° and ∠AOB = 90° **Proved.**